Many digital cameras have limited dynamic range and as a result, details of a scene may be missed while capturing an image. Examples of a conventional technique for high dynamic range (HDR) image generation include a multi-exposure image composition method, where the multi-exposure image compositing method includes capturing a plurality of images with different exposures and generating HDR data. An image pyramid is a type of multi-scale signal representation where repeated smoothing and subsampling operations are applied to a source image to generate a series of reduced resolution images. The exposure fusion method merges different parts of different weighted images which may differ according to image contrast levels, saturation levels, exposure levels, and so on. The technique then restores those weighted images seamlessly using pyramidal image decomposition.
Exposure fusion is generally effective when dealing with simple exposure conditions. However, most HDR images consist of complex exposure conditions of a scene and therefore, details in over-exposed and/or under-exposed regions in the image may be lost. Specifically, higher pyramid levels may lose details of highlight and shadow regions and where lower pyramid level may lead to visible transitions in the luminance values from one region of the image to the other, also known as a halo effect.